package cn.edu.seig.textbook.utils;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

public class VerifyCode {
    public static String drawRandomText(int width, int height, BufferedImage verifyImg) {

        Graphics2D graphics = (Graphics2D) verifyImg.getGraphics();
        graphics.setColor(Color.WHITE);//设置画笔颜色-验证码背景色
        graphics.fillRect(0, 0, width, height);//填充背景
        graphics.setFont(new Font("微软雅黑", Font.BOLD, 24));

        //数字和字母的组合
        String baseNumLetter = "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

        StringBuilder builder = new StringBuilder();
        int x = 6;  //旋转原点的 x 坐标
        String ch;
        Random random = new Random();

        for (int i = 0; i < 4; i++) {
            graphics.setColor(getRandomColor());
            //设置字体旋转角度
            int degree = random.nextInt() % 30;  //角度小于30度
            int dot = random.nextInt(baseNumLetter.length());

            ch = baseNumLetter.charAt(dot) + "";
            builder.append(ch);

            //正向旋转
            graphics.rotate(degree * Math.PI / 180, x, 22);
            graphics.drawString(ch, x, 26);

            //反向旋转
            graphics.rotate(-degree * Math.PI / 180, x, 22);
            x += 24;
        }

        //画干扰线
        for (int i = 0; i < 6; i++) {
            // 设置随机颜色
            graphics.setColor(getRandomColor());
            // 随机画线
            graphics.drawLine(random.nextInt(width), random.nextInt(height),
                    random.nextInt(width), random.nextInt(height));
        }

        //添加噪点
        for (int i = 0; i < 100; i++) {
            int x1 = random.nextInt(width);
            int y1 = random.nextInt(height);
            graphics.setColor(getRandomColor());
            graphics.fillRect(x1, y1, 1, 1);
        }
        return builder.toString();
    }

    /**
     * 随机取色
     */
    private static Color getRandomColor() {
        Random ran = new Random();
        return new Color(ran.nextInt(256),
                ran.nextInt(256), ran.nextInt(256));
    }
}
